System and method for harq in cloud ran with large front haul latency

ABSTRACT

A system is enabled to perform error checking and other HARQ processes at a remote radio unit device in cloud RAN systems that have a large front haul latency. The remote radio unit device performs error checking on transmissions received from a mobile device and sends an acknowledgement (ACK) or negative acknowledgement (NACK) to the mobile device based on whether errors are found.

RELATED APPLICATION

The subject patent application is a continuation of, and claims priorityto, U.S. patent application Ser. No. 14/699,774, filed Apr. 29, 2015,and entitled “SYSTEM AND METHOD FOR HARQ IN CLOUD RAN WITH LARGE FRONTHAUL LATENCY,” the entirety of which application is hereby incorporatedby reference herein.

TECHNICAL FIELD

The subject disclosure relates to a system for enhanced hybrid automaticrepeat request to decrease latency in systems with large front haullatency in a mobile communications environment.

BACKGROUND

Hybrid automatic repeat request (HARQ) is a system of error checkingwhere transmissions from mobile devices are checked for errors. If thetransmission contains an error, a retransmission request is sent back tothe mobile device to resend the transmission. In synchronous uplinksystems, there are standards for scheduling so that a certain amount oftime is allotted to send the retransmission requirement. The system thatperforms the HARQ has traditionally been the baseband unit of an eNodeBin an LTE system.

Due to increasing demand, small cell deployments are being developedwith cloud radio access network (RAN) systems, where a portion of a basestation device (e.g., the baseband unit device of the eNodeB) maysupport multiple remote radio unit devices. The remote radio unitdevices, which are primarily used for transmission and reception ofradio signals from mobile devices, may be located at some distance fromthe baseband units, physical or virtual, and so the increased latencydue to the distance between the devices may negatively affect HARQperformance.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an example, non-limiting embodiment of a block diagram showinga system showing multiple remote radio unit devices being supported by abaseband unit device in accordance with various aspects describedherein.

FIG. 2 is an example, non-limiting embodiment of a block diagram showinga system for error checking in a cloud RAN in accordance with variousaspects described herein.

FIG. 3 is an example, non-limiting embodiment of a block diagram showinga remote radio unit device in accordance with various aspects describedherein.

FIG. 4 is an example, non-limiting embodiment of a block diagram showinga timeline for error checking in accordance with various aspectsdescribed herein.

FIG. 5 is an example, non-limiting embodiment of a block diagram showinga timeline for error checking in accordance with various aspectsdescribed herein.

FIG. 6 illustrates a flow diagram of an example, non-limiting embodimentof a method for error checking at a remote radio unit device asdescribed herein.

FIG. 7 illustrates a flow diagram of an example, non-limiting embodimentof a method for error checking at a remote radio unit device asdescribed herein.

FIG. 8 illustrates a flow diagram of an example, non-limiting embodimentof a method for error checking at a remote radio unit device asdescribed herein.

FIG. 9 is a block diagram of an example, non-limiting embodiment of acomputing environment in accordance with various aspects describedherein.

FIG. 10 is a block diagram of an example, non-limiting embodiment of amobile network platform in accordance with various aspects describedherein.

DETAILED DESCRIPTION

One or more embodiments are now described with reference to thedrawings, wherein like reference numerals are used to refer to likeelements throughout. In the following description, for purposes ofexplanation, numerous specific details are set forth in order to providea thorough understanding of the various embodiments. It is evident,however, that the various embodiments can be practiced without thesespecific details (and without applying to any particular networkedenvironment or standard).

A system is provided to perform error checking and other HARQ processesat a remote radio unit device in cloud RAN systems that have a largefront haul latency. The remote radio unit device performs error checkingon transmissions received from a mobile device and sends anacknowledgement (ACK) or negative acknowledgement (NACK) to the mobiledevice based on whether errors are found. In another embodiment, theremote radio unit device can send an interim ACK to the mobile device,and then send a retransmission request if the baseband unit devicedetermines that there is an error in transmission. Both of thesetechniques allow for improved uplink throughput even in systems wherethere may be a high latency fronthaul connection.

In an embodiment, if a remote radio unit device is located at a greatenough distance from a baseband unit device that the latency in theconnection interferes with scheduling requirements for HARQ processing,a remote radio unit device can be provided that performs error checkingat the remote radio unit device, without waiting to hear back from thebaseband unit device whether transmissions contain errors. The remoteradio unit device can send an ACK or NACK to the mobile device directly.By enabling the remote radio unit device to perform error checking, theACK and NACK can be sent within the three millisecond time period thatis required for synchronous uplink retransmission.

In another embodiment, the remote radio unit device can send an interimor provisional acknowledgement to the mobile device upon reception of atransmission. The interim acknowledgement can be sent to the mobiledevice within the three millisecond time frame provided by the LTE HARQstandards, even if the remote radio unit device has not alreadydetermined whether the transmission contains an error. If thetransmission does not contain an error, an additional acknowledgementmay not need to be sent, but if the transmission does contain an error,a retransmission request can be sent after the interim acknowledgementwas sent. In an embodiment, the interim acknowledgement can be sent ifthe remote radio unit device is not able to perform the error checkingwithin time, or if a latency between the baseband unit device and theremote radio unit device is above a predetermined threshold.

For these considerations as well as other considerations, in one or moreembodiments, a remote radio unit device can comprise a processor and amemory that stores executable instructions that, when executed by theprocessor, facilitate performance of operations. The operations caninclude receiving a transmission from a mobile device and determiningwhether the transmission comprises an error. The operations can alsoinclude, in response to the determining indicating that the transmissiondoes not comprise the error, sending an acknowledgement to the mobiledevice and in response to the determining indicating that thetransmission does comprise the error, sending a retransmission requestto the mobile device.

In another embodiment, a method can include receiving, by a remote radiounit device comprising a processor, a transmission from a mobile device.The method can also include performing, by the remote radio unit device,error detection on the transmission. The method can also include, inresponse to not detecting an error, sending, by the remote radio unitdevice, an acknowledgement to the mobile device, or in response todetecting the error, sending, by the remote radio unit device, aretransmission request to the mobile device.

In yet another embodiment, a computer-readable storage device storingexecutable instructions that, in response to execution, cause a systemcomprising a processor to perform operations. The operations can includereceiving a transmission from a mobile device. The operations can alsoinclude determining whether the transmission comprises an error, whereinthe determining is performed at a remote radio unit. The operations canfurther include sending an acknowledgement in response to thedetermining indicating that the transmission does not comprise the erroror sending a retransmission request in response to the determiningindicating that the transmission does comprise the error.

Turning now to FIG. 1, illustrated is an example, non-limitingembodiment of a block diagram 100 showing a system showing multipleremote radio unit devices 104, 106, and 108 being supported by abaseband unit device 102 in accordance with various aspects describedherein. A fronthaul link 110 connects the remote radio units 104, 106,and 108, and the latency of the fronthaul link 110 can vary depending onhow far away the remote radio unit devices are from the baseband unitdevice 102.

The uplink connection from a mobile device to the eNodeB, whichcomprises both the remote radio unit devices 104, 106, and 108 and thebaseband unit device 102 is synchronous according to current 3GPPspecifications. This reduces the interaction between the mobile deviceand the eNodeB, and simplifies the operation for mobile device as well.However, to meet the requirement of synchronous uplink retransmission,the eNodeB may need to complete the processing of uplink channel datawithin a 3 ms time period so that if a retransmission needs to be sent,the eNodeB can alert the mobile device to resend the transmission by theeighth transmission time interval, or 8 ms after the first transmissionwas sent. If this time requirement is not met, the mobile device cannotresend the data until the sixteenth transmission time interval, or 16 msafter the first transmission is sent, which can slow down the uplinkthroughput bandwidth.

If there is a large distance between remote radio units 104, 106, and108 and the baseband unit device 102, or if baseband unit device 102 isprovided as a cloud service, there can be a large fronthaul delay onconnection 110 such that the 3 ms processing time may not be realizedfor HARQ error detection at the baseband unit device 102. In order toovercome this difficulty, error detection can be implemented at theremote radio unit devices 104, 106, and 108 so that the latency causeddue to connection 110 is no longer relevant. In addition, the remoteradio unit devices can issue interim acknowledgements so that new datais transmitted every 8 ms, but if an error is detected, then aretransmission request can be sent by the remote radio unit device tothe mobile device. This retransmission request can be sent at a latertime, and the mobile device can retransmit data that was stored in abuffer on the mobile device.

Turning now to FIG. 2, illustrated is an example, non-limitingembodiment of a block diagram 200 showing a system for error checking ina cloud RAN in accordance with various aspects described herein.

In an embodiment, if an eNodeB is split with a local remote radio unitdevice 204 and a cloud provisioned baseband unit device 202 such that alatency in the connection interferes with scheduling requirements forHARQ processing, the remote radio unit device can perform error checkingat the remote radio unit device 204, without waiting to hear back fromthe baseband unit device 202 whether transmissions contain errors. Theremote radio unit device can send an ACK or NACK to the mobile device206 directly. By enabling the remote radio unit device 204 to performerror checking, the ACK and NACK can be sent within the threemillisecond time period that is required for synchronous uplinkretransmission.

In an embodiment, the mobile device 206 can send transmissions that areencoded with an error detecting code such as cyclic redundancy check.The remote radio unit device 204 can check for errors based on the errordetecting code, and if there are errors, request a retransmission. Inother embodiments, the mobile device 206 can send transmissions that areencoded with a forward error correction code and an error detecting code(e.g., Reed-Solomon code). The forward error correction code can be usedby the remote radio unit device 204 to decode the data and/or correcterrors in the transmission, and retransmission is only requested in caseif the errors in the transmission are uncorrectable.

In a typical eNodeB, the general operational split between the remoteradio unit and the baseband unit is that the remote radio unit performslayer 1 processing, while the baseband unit performs layer 2 processingand above. In an embodiment of the subject disclosure though, the remoteradio unit device 204 can perform some layer 2 processing ontransmissions received from mobile device 204.

In an embodiment, remote radio unit device 204 can include part of thescheduler of the eNodeB handles retransmission of data, while the partof the scheduler that resides in the baseband unit device 202 handlesnew transmissions. Since the HARQ retransmission may need to follow timeconstraints imposed by the synchronous standards, the retransmission canbe handled at the remote radio unit device 204 without the latencyimposed by the connection to the baseband unit device 202 in the cloudRAN. In an embodiment, the remote radio unit device 204 can receivescheduling information associated with the new transmission from thebaseband unit device 202. The scheduling information can provide aschedule for requesting new transmissions from the mobile device 206 andcan include intervals, or breaks between the new transmissions requeststo allow for the retransmission requests determined, and generated byremote radio unit device 204. The number of intervals, interval rate, orthe length of the intervals can be adjusted based on the expected orrealized error rate of transmissions received from the mobile device206. For instance, if environmental conditions, or loading, orinterference, are such that the error rate is measured or expected to behigher, the baseband unit device 202 can send scheduling information tothe remote radio unit device 204 that has an increased number ofintervals to account for the higher number of retransmission requests.

In an embodiment, an interim acknowledgement can be sent from the remoteradio unit device 204 to the mobile device 206 regardless of whether anerror has been detected or not. If the fronthaul delay in overallprocessing at both the remote radio unit device 204 and the basebandunit device 202 is greater than 3 ms, then the interim acknowledgmentcan be sent on a physical HARQ indicator channel (PHICH). The remoteradio unit device 204 can either ask for a retransmission of data or anew data transmission using a toggled new data indicator bit on aPhysical Downlink Control Channel (PDCCH) after the data received in thetransmission on the Physical Uplink Shared Channel (PUSCH) is received.

In an embodiment, the remote radio unit device 204 can initiate checkingfor errors, and if the processing is finished within 3 ms, the remoteradio unit device 204 can send the ACK/NACK on PHICH. If the processing,either at the baseband unit device 202 or at remote radio unit device204, has not been performed within the time frame, the remote radio unitdevice 204 can send a temporary or interim ACK on PHICH. The interimacknowledgement prevents unnecessary retransmissions, since the mobiledevice 206 will retransmit unless an ACK is received. When the ACK isreceived, interim or not, the mobile device 206 can buffer thetransmission for a short time, and if a NACK or a retransmission requestrelated to the first transmission is received, the mobile device 206 canretransmit the buffered data.

In the case when a NACK is supposed to be sent, the dummy ACK halts theprocess of non-adaptive retransmission but it gives more control forlater retransmission, requested on PDCCH with possibly differentresource blocks and MCS, while using less number of retransmissions.

In another embodiment, the remote radio unit device 204 can check forHARQ transmission errors in transmissions from the mobile device 206 atthe remote radio unit device 204. If data is received without errors,then an ACK can be sent on PHICH to the mobile device 206, and if aretransmission is required by the baseband unit device 202, the remoteradio unit device 204 can send a indicator to 0 on downlink controlinformation (DCI format 0) on PDCCH. If an error is detected however atthe remote radio unit 204, then the remote radio unit device 204 canitself send a NACK on PHICH.

Turning now to FIG. 3, illustrated is an example, non-limitingembodiment of a block diagram 300 showing a remote radio unit device 302in accordance with various aspects described herein.

In an embodiment, if an eNodeB is split with a local remote radio unitdevice 302 and a cloud provisioned baseband unit device 312 such that alatency in the connection interferes with scheduling requirements forHARQ processing, the remote radio unit device 302 can performs errorchecking at the remote radio unit device 302, without waiting to hearback from the baseband unit device 312 whether a transmission from amobile device 314 contains an error. The remote radio unit device 302can send an ACK or NACK to the mobile device 314 directly. By enablingthe remote radio unit device 302 to perform error checking, the ACK andNACK can be sent within the three millisecond time period that isrequired for synchronous uplink retransmission.

In an embodiment, an RF component 310 can receive a transmission frommobile device 314 via a radio frequency (RF) connection. An errorchecking component 304 can begin to check the transmission for errors.The error checking component 304 can check for errors based on an errordetecting code that was encoded with the data in the transmission, andif there are errors, request a retransmission. In other embodiments, theerror checking component 304 can try to correct the errors using aforward error correcting code that was encoded with the data and requesta retransmission if the data is uncorrectable.

In an embodiment, a fronthaul component 308 can transmit the receiveddata to the baseband unit device 312 via a fronthaul link. The basebandunit device 312 can also perform HARQ processing, and initiate aretransmission or new data transmission via the fronthaul component 308.A scheduler component 306 can monitor the length of time betweenreceiving the transmission at the RF component 310 the error checkingprocessing by the error checking component 304. If the schedulercomponent 306 determines that the 3 ms time period for sending anACK/NACK will not be met, the scheduler component 306 can initiatesending of an ACK to the mobile device 314 via the RF component 310. TheACK can be an interim ACK, and if the error checking component 304determines that there is an error, a retransmission request can be sentto the mobile device 314.

In an embodiment, the error checking component 304 can determine whetheror not the transmission contains an error within 3 ms, and an ACK can besent if no error is found, or an NACK can be sent if an error is found.

In an embodiment, the scheduler component 306 can determine the latencybetween the baseband unit device 312 and the remote radio unit device302. If the latency is small/low enough that the baseband unit device312 can perform HARQ processing on data within the time constraintsimposed by synchronous uplink standards, then the remote radio unitdevice 302 will just perform layer 1 processing on the transmissionsreceived from mobile device 314 and forward the transmissions to thebaseband unit device 312 for all layer 2 and above processing. Ifscheduler component 306 determines that the latency is high enough thatthe HARQ processing at the baseband unit device 312 will not meet thetime requirements, then the scheduler component 306 can initiate errorchecking at the remote radio unit device 302 by error checking component304.

Turning now to FIG. 4, illustrated is an example, non-limitingembodiment of a block diagram showing a timeline 400 for error checkingin accordance with various aspects described herein. The timeline 400shown in FIG. 4 illustrates an embodiment where the remote radio unitperforms error checking and sends a NACK indicating that an error hasbeen found.

In an embodiment, each of the time period divisions in the timeline 400indicate a transmission time interval of 1 ms. There are 8TTIs, or 8 msbetween when the UE, or the mobile device, can send packets of data tothe remote radio unit. At 402, the eNodeB, or more specifically, theRRU, sends an uplink grant to the mobile device where it is receivedshortly thereafter. At 404, the UE transmits the data on PUSCH and it isreceived by the RRU shortly thereafter. At 406, after the PUSCH data isreceived, the remote radio unit can begin processing the transmission tocheck for errors. At 410, after the RRU determines that there is anerror, the NACK can be sent to the mobile device where it is received at412 which gives time for the mobile device to resend the transmission at414.

If the RRU did not check for errors, the time period 408 denotes thelength of time for processing by the BBU, which may not give enough timefor the mobile device to resend the data 414. If the mobile devicemisses the 414 time period, it may have to wait another 8 TTIs to resendthe data, thus causing a 16 ms delay in case of transmission errors,versus an 8 ms delay if the RRU is performing error checking.

Turning now to FIG. 5, illustrated is an example, non-limitingembodiment of a block diagram showing a timeline 500 for error checkingin accordance with various aspects described herein. The timeline 500shown in FIG. 5 illustrates an embodiment where the remote radio unitsends an interim acknowledgement.

In an embodiment, each of the time period divisions in the timeline 500indicate a transmission time interval of 1 ms. There are 8TTIs, or 8 msbetween when the UE, or the mobile device, can send packets of data tothe remote radio unit. At 502, the eNodeB, or more specifically, theRRU, sends an uplink grant to the mobile device where it is receivedshortly thereafter. At 504, the UE transmits the data on PUSCH and it isreceived by the RRU shortly thereafter. At 508, after the PUSCH data isreceived, the remote radio unit sends a dummy, or interimacknowledgement, even though the HARQ processing by the eNodeB is stillbeing performed as shown at 506. At 512, after the eNodeB processingfinished, the RRU can send a retransmission request on PDCCH and themobile device can resend the transmission at 514.

FIGS. 6-8 illustrates a process in connection with the aforementionedsystems. The processes in FIGS. 6-8 can be implemented for example bysystems 100-300 as illustrated in FIGS. 1-3 respectively. While forpurposes of simplicity of explanation, the methods are shown anddescribed as a series of blocks, it is to be understood and appreciatedthat the claimed subject matter is not limited by the order of theblocks, as some blocks may occur in different orders and/or concurrentlywith other blocks from what is depicted and described herein. Moreover,not all illustrated blocks may be required to implement the methodsdescribed hereinafter.

FIG. 6 illustrates a flow diagram of an example, non-limiting embodimentof a method for error checking at a remote radio unit device asdescribed herein. The method 600 can begin at 602 where the methodincludes receiving, by a remote radio unit device comprising aprocessor, a transmission from a mobile device. At 604, the methodincludes performing, by the remote radio unit device, error detection onthe transmission. An error checking component can begin to check thetransmission for errors at the remote radio unit device. The errorchecking component can check for errors based on an error detecting codethat was encoded with the data in the transmission, and if there areerrors, request a retransmission. In other embodiments, the errorchecking component can try to correct the errors using a forward errorcorrecting code that was encoded with the data and request aretransmission if the data is uncorrectable.

At 606, the method includes in response to not detecting an error,sending, by the remote radio unit device, an acknowledgement to themobile device, or in response to detecting the error, sending, by theremote radio unit device, a retransmission request to the mobile device.

FIG. 7 illustrates a flow diagram of an example, non-limiting embodimentof a method 700 for error checking at a remote radio unit device asdescribed herein. The method 700 can begin at 702 where the methodincludes sending, by the remote radio unit device, an interimacknowledgement to the mobile device. At 704, the method can includedetermining, by the remote radio unit device, that the transmissioncomprises an error based on receiving an indication of the error from abaseband unit device. At 706, the method can include sending, by theremote radio unit device, the retransmission request after sending theinterim acknowledgement.

FIG. 8 illustrates a flow diagram of an example, non-limiting embodimentof a method 800 for error checking at a remote radio unit device asdescribed herein.

At 802 the method can begin with the remote radio unit device receivinga transmission from a mobile device, and at 804 the remote radio unitdevice can initiate error checking. An error checking component on theremote radio unit device can begin to check the transmission for errorsat the remote radio unit device. The error checking component can checkfor errors based on an error detecting code that was encoded with thedata in the transmission, and if there are errors, request aretransmission. In other embodiments, the error checking component cantry to correct the errors using a forward error correcting code that wasencoded with the data and request a retransmission if the data isuncorrectable.

At 806, a scheduling function of the remote radio unit device candetermine whether the error checking is going to take longer than 3milliseconds. The length can be based on the type and/or complexity ofthe error checking. The duration of the error checking can also be basedon a fronthaul latency between the remote radio unit device and thebaseband unit device.

If the scheduler determines that the error checking will take less than3 milliseconds, then the error checking is completed at the RRU at 808and then it is determined whether there is an error at 810. If there isan error, a NACK is transmitted to the mobile device at 814, and aretransmission is then received a short time later at 816. If there isno error, then an ACK is sent at 812.

If the scheduler determines that the error checking will take longerthan 3 seconds, then an interim acknowledgement can be sent at 818. Oncethe error checking is completed it is determined whether an error ispresent at 820. If there is an error, than a NACK can be sent, but ifthere is no error, than nothing needs to be done, and a new transmissioncan be received at 822.

Referring now to FIG. 9, there is illustrated a block diagram of acomputing environment in accordance with various aspects describedherein. For example, in some embodiments, the computer can be or beincluded within the remote radio unit device 104, 106, 108, 204, or 302or within the baseband unit device 102, 202, or 312.

In order to provide additional context for various embodiments describedherein, FIG. 9 and the following discussion are intended to provide abrief, general description of a suitable computing environment 900 inwhich the various embodiments of the embodiment described herein can beimplemented. While the embodiments have been described above in thegeneral context of computer-executable instructions that can run on oneor more computers, those skilled in the art will recognize that theembodiments can be also implemented in combination with other programmodules and/or as a combination of hardware and software.

Generally, program modules include routines, programs, components, datastructures, etc., that perform particular tasks or implement particularabstract data types. Moreover, those skilled in the art will appreciatethat the inventive methods can be practiced with other computer systemconfigurations, including single-processor or multiprocessor computersystems, minicomputers, mainframe computers, as well as personalcomputers, hand-held computing devices, microprocessor-based orprogrammable consumer electronics, and the like, each of which can beoperatively coupled to one or more associated devices.

The terms “first,” “second,” “third,” and so forth, as used in theclaims, unless otherwise clear by context, is for clarity only anddoesn't otherwise indicate or imply any order in time. For instance, “afirst determination,” “a second determination,” and “a thirddetermination,” does not indicate or imply that the first determinationis to be made before the second determination, or vice versa, etc.

The illustrated embodiments of the embodiments herein can be alsopracticed in distributed computing environments where certain tasks areperformed by remote processing devices that are linked through acommunications network. In a distributed computing environment, programmodules can be located in both local and remote memory storage devices.

Computing devices typically include a variety of media, which caninclude computer-readable storage media and/or communications media,which two terms are used herein differently from one another as follows.Computer-readable storage media can be any available storage media thatcan be accessed by the computer and includes both volatile andnonvolatile media, removable and non-removable media. By way of example,and not limitation, computer-readable storage media can be implementedin connection with any method or technology for storage of informationsuch as computer-readable instructions, program modules, structured dataor unstructured data.

Computer-readable storage media can include, but are not limited to,random access memory (RAM), read only memory (ROM), electricallyerasable programmable read only memory (EEPROM), flash memory or othermemory technology, compact disk read only memory (CD-ROM), digitalversatile disk (DVD) or other optical disk storage, magnetic cassettes,magnetic tape, magnetic disk storage or other magnetic storage devicesor other tangible and/or non-transitory media which can be used to storedesired information. In this regard, the terms “tangible” or“non-transitory”herein as applied to storage, memory orcomputer-readable media, are to be understood to exclude onlypropagating transitory signals per se as modifiers and do not relinquishrights to all standard storage, memory or computer-readable media thatare not only propagating transitory signals per se.

Computer-readable storage media can be accessed by one or more local orremote computing devices, e.g., via access requests, queries or otherdata retrieval protocols, for a variety of operations with respect tothe information stored by the medium.

Communications media typically embody computer-readable instructions,data structures, program modules or other structured or unstructureddata in a data signal such as a modulated data signal, e.g., a carrierwave or other transport mechanism, and includes any information deliveryor transport media. The term “modulated data signal” or signals refersto a signal that has one or more of its characteristics set or changedin such a manner as to encode information in one or more signals. By wayof example, and not limitation, communication media include wired media,such as a wired network or direct-wired connection, and wireless mediasuch as acoustic, RF, infrared and other wireless media.

With reference again to FIG. 9, the example environment 900 forimplementing various embodiments of the aspects described hereinincludes a computer 902, the computer 902 including a processing unit904, a system memory 906 and a system bus 908. The system bus 908couples system components including, but not limited to, the systemmemory 906 to the processing unit 904. The processing unit 904 can beany of various commercially available processors. Dual microprocessorsand other multi-processor architectures can also be employed as theprocessing unit 904.

The system bus 908 can be any of several types of bus structure that canfurther interconnect to a memory bus (with or without a memorycontroller), a peripheral bus, and a local bus using any of a variety ofcommercially available bus architectures. The system memory 906 includesROM 910 and RAM 912. A basic input/output system (BIOS) can be stored ina non-volatile memory such as ROM, erasable programmable read onlymemory (EPROM), EEPROM, which BIOS contains the basic routines that helpto transfer information between elements within the computer 902, suchas during startup. The RAM 912 can also include a high-speed RAM such asstatic RAM for caching data.

The computer 902 further includes an internal hard disk drive (HDD) 914(e.g., EIDE, SATA), which internal hard disk drive 914 can also beconfigured for external use in a suitable chassis (not shown), amagnetic floppy disk drive (FDD) 916, (e.g., to read from or write to aremovable diskette 918) and an optical disk drive 920, (e.g., reading aCD-ROM disk 922 or, to read from or write to other high capacity opticalmedia such as the DVD). The hard disk drive 914, magnetic disk drive 916and optical disk drive 920 can be connected to the system bus 908 by ahard disk drive interface 924, a magnetic disk drive interface 926 andan optical drive interface 928, respectively. The interface 924 forexternal drive implementations includes at least one or both ofUniversal Serial Bus (USB) and Institute of Electrical and ElectronicsEngineers (IEEE) 994 interface technologies. Other external driveconnection technologies are within contemplation of the embodimentsdescribed herein.

The drives and their associated computer-readable storage media providenonvolatile storage of data, data structures, computer-executableinstructions, and so forth. For the computer 902, the drives and storagemedia accommodate the storage of any data in a suitable digital format.Although the description of computer-readable storage media above refersto a hard disk drive (HDD), a removable magnetic diskette, and aremovable optical media such as a CD or DVD, it should be appreciated bythose skilled in the art that other types of storage media which arereadable by a computer, such as zip drives, magnetic cassettes, flashmemory cards, cartridges, and the like, can also be used in the exampleoperating environment, and further, that any such storage media cancontain computer-executable instructions for performing the methodsdescribed herein.

A number of program modules can be stored in the drives and RAM 912,including an operating system 930, one or more application programs 932,other program modules 934 and program data 936. All or portions of theoperating system, applications, modules, and/or data can also be cachedin the RAM 912. The systems and methods described herein can beimplemented utilizing various commercially available operating systemsor combinations of operating systems.

A user can enter commands and information into the computer 902 throughone or more wired/wireless input devices, e.g., a keyboard 938 and apointing device, such as a mouse 940. Other input devices (not shown)can include a microphone, an infrared (IR) remote control, a joystick, agame pad, a stylus pen, touch screen or the like. These and other inputdevices are often connected to the processing unit 904 through an inputdevice interface 942 that can be coupled to the system bus 908, but canbe connected by other interfaces, such as a parallel port, an IEEE 1394serial port, a game port, a universal serial bus (USB) port, an IRinterface, etc.

A monitor 944 or other type of display device can be also connected tothe system bus 908 via an interface, such as a video adapter 946. Inaddition to the monitor 944, a computer typically includes otherperipheral output devices (not shown), such as speakers, printers, etc.

The computer 902 can operate in a networked environment using logicalconnections via wired and/or wireless communications to one or moreremote computers, such as a remote computer(s) 948. The remotecomputer(s) 948 can be a workstation, a server computer, a router, apersonal computer, portable computer, microprocessor-based entertainmentappliance, a peer device or other common network node, and typicallyincludes many or all of the elements described relative to the computer902, although, for purposes of brevity, only a memory/storage device 950is illustrated. The logical connections depicted include wired/wirelessconnectivity to a local area network (LAN) 952 and/or larger networks,e.g., a wide area network (WAN) 954. Such LAN and WAN networkingenvironments are commonplace in offices and companies, and facilitateenterprise-wide computer networks, such as intranets, all of which canconnect to a global communications network, e.g., the Internet.

When used in a LAN networking environment, the computer 902 can beconnected to the local network 952 through a wired and/or wirelesscommunication network interface or adapter 956. The adapter 956 canfacilitate wired or wireless communication to the LAN 952, which canalso include a wireless AP disposed thereon for communicating with thewireless adapter 956.

When used in a WAN networking environment, the computer 902 can includea modem 958 or can be connected to a communications server on the WAN954 or has other means for establishing communications over the WAN 954,such as by way of the Internet. The modem 958, which can be internal orexternal and a wired or wireless device, can be connected to the systembus 908 via the input device interface 942. In a networked environment,program modules depicted relative to the computer 902 or portionsthereof, can be stored in the remote memory/storage device 950. It willbe appreciated that the network connections shown are example and othermeans of establishing a communications link between the computers can beused.

The computer 902 can be operable to communicate with any wirelessdevices or entities operatively disposed in wireless communication,e.g., a printer, scanner, desktop and/or portable computer, portabledata assistant, communications satellite, any piece of equipment orlocation associated with a wirelessly detectable tag (e.g., a kiosk,news stand, restroom), and telephone. This can include Wireless Fidelity(Wi-Fi) and BLUETOOTH® wireless technologies. Thus, the communicationcan be a predefined structure as with a conventional network or simplyan ad hoc communication between at least two devices.

Wi-Fi can allow connection to the Internet from a couch at home, a bedin a hotel room or a conference room at work, without wires. Wi-Fi is awireless technology similar to that used in a cell phone that enablessuch devices, e.g., computers, to send and receive data indoors and out;anywhere within the range of a base station. Wi-Fi networks use radiotechnologies called IEEE 802.11 (a, b, g, n, ac, etc.) to providesecure, reliable, fast wireless connectivity. A Wi-Fi network can beused to connect computers to each other, to the Internet, and to wirednetworks (which can use IEEE 802.3 or Ethernet). Wi-Fi networks operatein the unlicensed 2.4 and 5 GHz radio bands, at an 11 Mbps (802.11a) or54 Mbps (802.11b) data rate, for example or with products that containboth bands (dual band), so the networks can provide real-worldperformance similar to the basic 10BaseT wired Ethernet networks used inmany offices.

FIG. 10 presents an example embodiment 1000 of a mobile network platform1010 that can implement and exploit one or more aspects of the disclosedsubject matter described herein. Generally, wireless network platform1010 can include components, e.g., nodes, gateways, interfaces, servers,or disparate platforms, that facilitate both packet-switched (PS) (e.g.,internet protocol (IP), frame relay, asynchronous transfer mode (ATM))and circuit-switched (CS) traffic (e.g., voice and data), as well ascontrol generation for networked wireless telecommunication. As anon-limiting example, wireless network platform 1010 can be included intelecommunications carrier networks, and can be considered carrier-sidecomponents as discussed elsewhere herein. Mobile network platform 1010includes CS gateway node(s) 1012 which can interface CS traffic receivedfrom legacy networks like telephony network(s) 1040 (e.g., publicswitched telephone network (PSTN), or public land mobile network (PLMN))or a signaling system #7 (SS7) network 1070. Circuit switched gatewaynode(s) 1012 can authorize and authenticate traffic (e.g., voice)arising from such networks. Additionally, CS gateway node(s) 1012 canaccess mobility, or roaming, data generated through SS7 network 1070;for instance, mobility data stored in a visited location register (VLR),which can reside in memory 1030. Moreover, CS gateway node(s) 1012interfaces CS-based traffic and signaling and PS gateway node(s) 1018.As an example, in a 3GPP UMTS network, CS gateway node(s) 1012 can berealized at least in part in gateway GPRS support node(s) (GGSN). Itshould be appreciated that functionality and specific operation of CSgateway node(s) 1012, PS gateway node(s) 1018, and serving node(s) 1016,is provided and dictated by radio technology(ies) utilized by mobilenetwork platform 1010 for telecommunication.

In addition to receiving and processing CS-switched traffic andsignaling, PS gateway node(s) 1018 can authorize and authenticatePS-based data sessions with served mobile devices. Data sessions caninclude traffic, or content(s), exchanged with networks external to thewireless network platform 1010, like wide area network(s) (WANs) 1050,enterprise network(s) 1070, and service network(s) 1080, which can beembodied in local area network(s) (LANs), can also be interfaced withmobile network platform 1010 through PS gateway node(s) 1018. It is tobe noted that WANs 1050 and enterprise network(s) 1060 can embody, atleast in part, a service network(s) like IP multimedia subsystem (IMS).Based on radio technology layer(s) available in technology resource(s)1017, packet-switched gateway node(s) 1018 can generate packet dataprotocol contexts when a data session is established; other datastructures that facilitate routing of packetized data also can begenerated. To that end, in an aspect, PS gateway node(s) 1018 caninclude a tunnel interface (e.g., tunnel termination gateway (TTG) in3GPP UMTS network(s) (not shown)) which can facilitate packetizedcommunication with disparate wireless network(s), such as Wi-Finetworks.

In embodiment 1000, wireless network platform 1010 also includes servingnode(s) 1016 that, based upon available radio technology layer(s) withintechnology resource(s) 1017, convey the various packetized flows of datastreams received through PS gateway node(s) 1018. It is to be noted thatfor technology resource(s) 1017 that rely primarily on CS communication,server node(s) can deliver traffic without reliance on PS gatewaynode(s) 1018; for example, server node(s) can embody at least in part amobile switching center. As an example, in a 3GPP UMTS network, servingnode(s) 1016 can be embodied in serving GPRS support node(s) (SGSN).

For radio technologies that exploit packetized communication, server(s)1014 in wireless network platform 1010 can execute numerous applicationsthat can generate multiple disparate packetized data streams or flows,and manage (e.g., schedule, queue, format . . . ) such flows. Suchapplication(s) can include add-on features to standard services (forexample, provisioning, billing, customer support . . . ) provided bywireless network platform 1010. Data streams (e.g., content(s) that arepart of a voice call or data session) can be conveyed to PS gatewaynode(s) 1018 for authorization/authentication and initiation of a datasession, and to serving node(s) 1016 for communication thereafter. Inaddition to application server, server(s) 1014 can include utilityserver(s), a utility server can include a provisioning server, anoperations and maintenance server, a security server that can implementat least in part a certificate authority and firewalls as well as othersecurity mechanisms, and the like. In an aspect, security server(s)secure communication served through wireless network platform 1010 toensure network's operation and data integrity in addition toauthorization and authentication procedures that CS gateway node(s) 1012and PS gateway node(s) 1018 can enact. Moreover, provisioning server(s)can provision services from external network(s) like networks operatedby a disparate service provider; for instance, WAN 1050 or GlobalPositioning System (GPS) network(s) (not shown). Provisioning server(s)can also provision coverage through networks associated to wirelessnetwork platform 1010 (e.g., deployed and operated by the same serviceprovider), such as femto-cell network(s) (not shown) that enhancewireless service coverage within indoor confined spaces and offload RANresources in order to enhance subscriber service experience within ahome or business environment by way of UE 1075.

It is to be noted that server(s) 1014 can include one or more processorsconfigured to confer at least in part the functionality of macro networkplatform 1010. To that end, the one or more processor can execute codeinstructions stored in memory 1030, for example. It is should beappreciated that server(s) 1014 can include a content manager 1015,which operates in substantially the same manner as describedhereinbefore.

In example embodiment 1000, memory 1030 can store information related tooperation of wireless network platform 1010. Other operationalinformation can include provisioning information of mobile devicesserved through wireless platform network 1010, subscriber databases;application intelligence, pricing schemes, e.g., promotional rates,flat-rate programs, couponing campaigns; technical specification(s)consistent with telecommunication protocols for operation of disparateradio, or wireless, technology layers; and so forth. Memory 1030 canalso store information from at least one of telephony network(s) 1040,WAN 1050, enterprise network(s) 1060, or SS7 network 1070. In an aspect,memory 1030 can be, for example, accessed as part of a data storecomponent or as a remotely connected memory store.

In order to provide a context for the various aspects of the disclosedsubject matter, FIG. 10, and the following discussion, are intended toprovide a brief, general description of a suitable environment in whichthe various aspects of the disclosed subject matter can be implemented.While the subject matter has been described above in the general contextof computer-executable instructions of a computer program that runs on acomputer and/or computers, those skilled in the art will recognize thatthe disclosed subject matter also can be implemented in combination withother program modules. Generally, program modules include routines,programs, components, data structures, etc. that perform particulartasks and/or implement particular abstract data types.

In the subject specification, terms such as “store,” “storage,” “datastore,” data storage,” “database,” and substantially any otherinformation storage component relevant to operation and functionality ofa component, refer to “memory components,” or entities embodied in a“memory” or components comprising the memory. It will be appreciatedthat the memory components described herein can be either volatilememory or nonvolatile memory, or can include both volatile andnonvolatile memory, by way of illustration, and not limitation, volatilememory (see below), non-volatile memory (see below), disk storage (seebelow), and memory storage (see below). Further, nonvolatile memory canbe included in read only memory (ROM), programmable ROM (PROM),electrically programmable ROM (EPROM), electrically erasable ROM(EEPROM), or flash memory. Volatile memory can include random accessmemory (RAM), which acts as external cache memory. By way ofillustration and not limitation, RAM is available in many forms such assynchronous RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM),double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), SynchlinkDRAM (SLDRAM), and direct Rambus RAM (DRRAM). Additionally, thedisclosed memory components of systems or methods herein are intended tocomprise, without being limited to comprising, these and any othersuitable types of memory.

Moreover, it will be noted that the disclosed subject matter can bepracticed with other computer system configurations, includingsingle-processor or multiprocessor computer systems, mini-computingdevices, mainframe computers, as well as personal computers, hand-heldcomputing devices (e.g., PDA, phone, watch, tablet computers, netbookcomputers, . . . ), microprocessor-based or programmable consumer orindustrial electronics, and the like. The illustrated aspects can alsobe practiced in distributed computing environments where tasks areperformed by remote processing devices that are linked through acommunications network; however, some if not all aspects of the subjectdisclosure can be practiced on stand-alone computers. In a distributedcomputing environment, program modules can be located in both local andremote memory storage devices.

The embodiments described herein can employ artificial intelligence (AI)to facilitate automating one or more features described herein. Theembodiments (e.g., in connection with automatically identifying acquiredcell sites that provide a maximum value/benefit after addition to anexisting communication network) can employ various AI-based schemes forcarrying out various embodiments thereof. Moreover, the classifier canbe employed to determine a ranking or priority of the each cell site ofthe acquired network. A classifier is a function that maps an inputattribute vector, x=(x1, x2, x3, x4, . . . , xn), to a confidence thatthe input belongs to a class, that is, f(x)=confidence(class). Suchclassification can employ a probabilistic and/or statistical-basedanalysis (e.g., factoring into the analysis utilities and costs) toprognose or infer an action that a user desires to be automaticallyperformed. A support vector machine (SVM) is an example of a classifierthat can be employed. The SVM operates by finding a hypersurface in thespace of possible inputs, which the hypersurface attempts to split thetriggering criteria from the non-triggering events. Intuitively, thismakes the classification correct for testing data that is near, but notidentical to training data. Other directed and undirected modelclassification approaches include, e.g., naïve Bayes, Bayesian networks,decision trees, neural networks, fuzzy logic models, and probabilisticclassification models providing different patterns of independence canbe employed. Classification as used herein also is inclusive ofstatistical regression that is utilized to develop models of priority.

As will be readily appreciated, one or more of the embodiments canemploy classifiers that are explicitly trained (e.g., via a generictraining data) as well as implicitly trained (e.g., via observing UEbehavior, operator preferences, historical information, receivingextrinsic information). For example, SVMs can be configured via alearning or training phase within a classifier constructor and featureselection module. Thus, the classifier(s) can be used to automaticallylearn and perform a number of functions, including but not limited todetermining according to a predetermined criteria which of the acquiredcell sites will benefit a maximum number of subscribers and/or which ofthe acquired cell sites will add minimum value to the existingcommunication network coverage, etc.

As used in this application, in some embodiments, the terms “component,”“system” and the like are intended to refer to, or include, acomputer-related entity or an entity related to an operational apparatuswith one or more specific functionalities, wherein the entity can beeither hardware, a combination of hardware and software, software, orsoftware in execution. As an example, a component may be, but is notlimited to being, a process running on a processor, a processor, anobject, an executable, a thread of execution, computer-executableinstructions, a program, and/or a computer. By way of illustration andnot limitation, both an application running on a server and the servercan be a component. One or more components may reside within a processand/or thread of execution and a component may be localized on onecomputer and/or distributed between two or more computers. In addition,these components can execute from various computer readable media havingvarious data structures stored thereon. The components may communicatevia local and/or remote processes such as in accordance with a signalhaving one or more data packets (e.g., data from one componentinteracting with another component in a local system, distributedsystem, and/or across a network such as the Internet with other systemsvia the signal). As another example, a component can be an apparatuswith specific functionality provided by mechanical parts operated byelectric or electronic circuitry, which is operated by a software orfirmware application executed by a processor, wherein the processor canbe internal or external to the apparatus and executes at least a part ofthe software or firmware application. As yet another example, acomponent can be an apparatus that provides specific functionalitythrough electronic components without mechanical parts, the electroniccomponents can include a processor therein to execute software orfirmware that confers at least in part the functionality of theelectronic components. While various components have been illustrated asseparate components, it will be appreciated that multiple components canbe implemented as a single component, or a single component can beimplemented as multiple components, without departing from exampleembodiments.

Further, the various embodiments can be implemented as a method,apparatus or article of manufacture using standard programming and/orengineering techniques to produce software, firmware, hardware or anycombination thereof to control a computer to implement the disclosedsubject matter. The term “article of manufacture” as used herein isintended to encompass a computer program accessible from anycomputer-readable device or computer-readable storage/communicationsmedia. For example, computer readable storage media can include, but arenot limited to, magnetic storage devices (e.g., hard disk, floppy disk,magnetic strips), optical disks (e.g., compact disk (CD), digitalversatile disk (DVD)), smart cards, and flash memory devices (e.g.,card, stick, key drive). Of course, those skilled in the art willrecognize many modifications can be made to this configuration withoutdeparting from the scope or spirit of the various embodiments.

In addition, the words “example” and “exemplary” are used herein to meanserving as an instance or illustration. Any embodiment or designdescribed herein as “example” or “exemplary” is not necessarily to beconstrued as preferred or advantageous over other embodiments ordesigns. Rather, use of the word example or exemplary is intended topresent concepts in a concrete fashion. As used in this application, theterm “or” is intended to mean an inclusive “or” rather than an exclusive“or”. That is, unless specified otherwise or clear from context, “Xemploys A or B” is intended to mean any of the natural inclusivepermutations. That is, if X employs A; X employs B; or X employs both Aand B, then “X employs A or B” is satisfied under any of the foregoinginstances. In addition, the articles “a” and “an” as used in thisapplication and the appended claims should generally be construed tomean “one or more” unless specified otherwise or clear from context tobe directed to a singular form.

Moreover, terms such as “user equipment,” “mobile station,” “mobile,”subscriber station,” “access terminal,” “terminal,” “handset,” “mobiledevice” (and/or terms representing similar terminology) can refer to awireless device utilized by a subscriber or user of a wirelesscommunication service to receive or convey data, control, voice, video,sound, gaming or substantially any data-stream or signaling-stream. Theforegoing terms are utilized interchangeably herein and with referenceto the related drawings.

Furthermore, the terms “user,” “subscriber,” “customer,” “consumer” andthe like are employed interchangeably throughout, unless contextwarrants particular distinctions among the terms. It should beappreciated that such terms can refer to human entities or automatedcomponents supported through artificial intelligence (e.g., a capacityto make inference based, at least, on complex mathematical formalisms),which can provide simulated vision, sound recognition and so forth.

As employed herein, the term “processor” can refer to substantially anycomputing processing unit or device comprising, but not limited tocomprising, single-core processors; single-processors with softwaremultithread execution capability; multi-core processors; multi-coreprocessors with software multithread execution capability; multi-coreprocessors with hardware multithread technology; parallel platforms; andparallel platforms with distributed shared memory. Additionally, aprocessor can refer to an integrated circuit, an application specificintegrated circuit (ASIC), a digital signal processor (DSP), a fieldprogrammable gate array (FPGA), a programmable logic controller (PLC), acomplex programmable logic device (CPLD), a discrete gate or transistorlogic, discrete hardware components or any combination thereof designedto perform the functions described herein. Processors can exploitnano-scale architectures such as, but not limited to, molecular andquantum-dot based transistors, switches and gates, in order to optimizespace usage or enhance performance of user equipment. A processor canalso be implemented as a combination of computing processing units.

What has been described above includes mere examples of variousembodiments. It is, of course, not possible to describe everyconceivable combination of components or methodologies for purposes ofdescribing these examples, but one of ordinary skill in the art canrecognize that many further combinations and permutations of the presentembodiments are possible. Accordingly, the embodiments disclosed and/orclaimed herein are intended to embrace all such alterations,modifications and variations that fall within the spirit and scope ofthe appended claims. Furthermore, to the extent that the term “includes”is used in either the detailed description or the claims, such term isintended to be inclusive in a manner similar to the term “comprising” as“comprising” is interpreted when employed as a transitional word in aclaim.

What is claimed is:
 1. A remote radio unit device, comprising: aprocessor; and a memory that stores executable instructions that, whenexecuted by the processor, facilitate performance of operations,comprising: receiving a transmission from a mobile device via a firstcommunication link; relaying the transmission to a baseband unit devicethat is remotely coupled to the remote radio unit device via a secondcommunications link; and in response to a passing of a latency periodwithout receiving an indication from the baseband unit device that thetransmission from the mobile device comprises an error, and based on aresult of a determination as to whether the transmission from the mobiledevice contains the error, sending a message to the mobile device,wherein the message is usable by the mobile device to determine whetherto retransmit the transmission.
 2. The remote radio unit device of claim1, wherein the latency period is between the remote radio unit deviceand the baseband unit device and is greater than three milliseconds. 3.The remote radio unit device of claim 2, wherein the transmission is afirst transmission, and wherein the operations further comprise:receiving scheduling information associated with a second transmissionfrom the baseband unit device.
 4. The remote radio unit device of claim3, wherein the message is a first retransmission request, and whereinthe operations further comprise: in response to receiving the schedulinginformation, sending a second retransmission request to the mobiledevice to transmit the second transmission.
 5. The remote radio unitdevice of claim 1, wherein the baseband unit device is part of a cloudradio access network.
 6. The remote radio unit device of claim 3,wherein the receiving the scheduling information further comprisesreceiving the scheduling information associated with the firsttransmission, wherein the scheduling information comprises apredetermined interval between the first transmission and the secondtransmission, and wherein the message is sent during the predeterminedinterval.
 7. The remote radio unit device of claim 6, wherein thepredetermined interval is based on an error rate associated withtransmissions received from the mobile device, and wherein thetransmissions comprise the first transmission and the secondtransmission.
 8. The remote radio unit device of claim 1, wherein themessage was sent within three milliseconds of the receiving thetransmission.
 9. The remote radio unit device of claim 1, wherein thedetermination as to whether the transmission contains the errorcomprises using an error detecting code to check the transmission forthe error.
 10. The remote radio unit device of claim 1, wherein theoperations further comprise: receiving a retransmission of thetransmission, from the mobile device, in response to the sending themessage.
 11. The remote radio unit device of claim 1, wherein theoperations further comprise: decoding the transmission prior to thedetermination as to whether the transmission contains the error.
 12. Amethod, comprising: receiving, by a remote radio unit device comprisinga processor, a transmission from a mobile device via a firstcommunications link after receiving the transmission from the mobiledevice; relaying, by the remote radio unit device, the transmission to abaseband unit device that is remotely coupled to the remote radio unitdevice via a second communications link; and in response to a passing ofa latency period without receiving, by the remote radio unit device, anindication from the baseband unit device that the transmission from themobile device comprises an error, and in response to a determination bythe remote radio unit device that the transmission from the mobiledevice comprises the error, sending, by the remote radio unit device, amessage to the mobile device, wherein the message comprises informationusable by the mobile device to retransmit the transmission.
 13. Themethod of claim 12, wherein the transmission is a first transmission,and wherein the method further comprises: receiving, by the remote radiounit device, scheduling information associated with a secondtransmission from the baseband unit device.
 14. The method of claim 13,wherein the receiving the scheduling information comprises receiving thescheduling information associated with the first transmission, andwherein the scheduling information comprises a predetermined intervalbetween the first transmission and the second transmission, and whereinthe message is sent during the predetermined interval.
 15. The method ofclaim 14, wherein the predetermined interval is based on an error rateassociated with transmissions received from the mobile device, andwherein the transmissions comprise the first transmission and the secondtransmission.
 16. The method of claim 12, wherein the latency period isbetween the remote radio unit device and a baseband unit device and isgreater than three milliseconds.
 17. The method of claim 12, furthercomprising: receiving, by the remote radio unit device, a retransmissionof the transmission, from the mobile device, in response to sending themessage.
 18. A computer-readable storage device storing executableinstructions that, in response to execution, cause a processor of aremote radio unit device to perform operations, comprising: receiving,by the remote radio unit device, a transmission from a mobile device viaa first communications link; after receiving the transmission from themobile device, relaying, by the remote radio unit device, thetransmission to a baseband unit device that is remotely coupled to theremote radio unit device via a second communications link; and inresponse to an elapsing of a latency period without receiving, by theremote radio unit device, an indication from the baseband unit devicethat the transmission from the mobile device comprises an error, andbased on an outcome of a determination by the remote radio unit deviceas to whether the transmission from the mobile device comprises theerror, sending, by the remote radio unit device, a message to the mobiledevice, wherein the message is able to be used by the mobile device todetermine whether to retransmit the transmission.
 19. Thecomputer-readable storage device of claim 18, wherein the latency periodis between the remote radio unit device and the baseband unit device andis greater than three milliseconds.
 20. The computer-readable storagedevice of claim 18, wherein the message is a first retransmissionrequest, and wherein the operations further comprise: receivingscheduling information associated with a second retransmission requestfrom the baseband unit device, wherein the scheduling informationcomprises an interval between the second retransmission request and thefirst retransmission request.